item not received

I bought something on ebay on the 5th of July and paid as soon as the auction ended. The listing said quick delivery and that it should be with me within 3 working days and by the LATEST the 12th of July.It still has not come so I went to email the seller and I seem to have opened a case?? this has never happened to me before when I try to contact the seller so ebay must have changed something.Am I likely to get a rude response from the seller for opening a case? (really didn't mean to I just want my item!)Ive been using ebay since 2005 and have never had anything not turn up so I am starting to get worried its not coming!